This invention is directed to resolving problems of the above indicated type. In particular, it is an object of this invention to form side tubes that have a sufficiently great resistance to pressure, and provide a short-arc ultra-high-pressure discharge lamp with such end tubes as well as a method for manufacturing such lamps.
In accordance with a first embodiment of the invention, a short-arc, ultra-high-pressure discharge lamp comprises a luminescent tube within which a pair of electrodes face each other and side tubes that extend from both sides of the luminescent tube and seal a portion of the electrodes, in which a small space is formed to enable the electrodes to expand and contract freely without compression along their axes that would be caused by a difference in the indices of expansion of the materials that make up the electrodes and the side tubes.
The method of manufacture of a short-arc, ultra-high-pressure discharge lamp in accordance with the invention comprises the following processes:                1) heating the electrodes and metallic foil to a temperature higher than the softening point of the side tubes, and then sealing the electrodes and metallic foil with the side tubes;        2) cooling the sealed side tubes to fix the metallic foil in the end tubes;        3) re-heating the portion of the side tube in which the electrode is sealed, softening the side tube and bringing the side tube into contact with the electrode while in a viscous, fluid state, so that the electrode can rub against the portion of the side tube that is in a viscous, fluid state; and        4) vibrating the re-heated side tube and electrode such that the temperature of the portion of the side tube in which the electrode is sealed reaches a temperature region between the side tube's softening point and its annealing point when the side tube softens and contacts the electrode while in a viscous, fluid state, and the electrode can rub against the portion of the side tube that is in a viscous, fluid state.        